1. Field of the Invention
The present invention relates to a power feeding system, a power feeding device, and a power feeding method.
2. Description of the Related Art
In recent years, there has been known a power feeding system for supplying electric power by wireless via electromagnetic induction or electromagnetic coupling between a feeding coil and a receiving coil (see, for example, Japanese Patent Application Laid-open No. 2006-60909). Such power feeding system is used for charging a battery included in a device such as a mobile phone terminal and a personal digital assistant (PDA), for example.
By the way, heat generated when a metallic foreign object is placed on the feeding coil may become a problem. The above-mentioned power feeding system is configured to suppress heat generation caused by the metallic foreign object by detecting the metallic foreign object based on the magnitude of a peak voltage of a voltage of the feeding coil, for example. In the above-mentioned power feeding system, however, it is difficult to accurately detect the metallic foreign object based on the material and thickness of the metallic foreign object, for example. Demands are therefore made on a power feeding system capable of appropriately suppressing heat generation caused by the metallic foreign object.